Have you ever wondered how tabby cats get their
stripes? Or why all cats don't have the same stripe patterns? Along a
cat's nineteen pairs of chromosomes, there are genes, which make up
the genome. Each breed of cat has its own dominant genes, and
different genotypes and phenotypes that determine the pigments in its
fur, the texture of its fur, the pattern of its fur, and there are
different genes for cats that grow no fur at all. All cats have genes
that affect the way they look, but one of the most distinct is the
striped and blotched pattern look that tabby cats have in their fur.
There has also been recent discoveries made in why all stripes are
not created equal.
An
example of how genes can affect the patterns in cat fur is a pattern
known as Agouti. Some cats have different colored bands along the
shafts of their tails, and the gene that causes this pattern is the
“Agouti Signaling Protein,” and a mutation or change in this gene
can have drastic affects on the pattern in a cat's fur. The banding
is based on the dominance of the Agouti gene and occurs when a cat
carries one or two copies of the gene. When the banded fur and solid
fur alternate, it is called tabbying, which is common in many cats.
If a cat has two copies of the non-agouti gene, then the fur will be
solid. In most tabby cats, the stripes are defined and evenly spaced.
There is also the tabby gene, as well, that effect the pattern. There
are three different stripe patterns which are inherited through the
tabby gene: Mackerel, Classic, and Abyssinian. A mutation in any of
these genes can cause variations of those patterns.
In a recent study, there was a discovery of a mutation
in the genomes in domestic tabbies which may even explain further
into how cats get blotches instead of stripes. The gene mutation is
called the “Taqpep mutation.” Researchers found that blotched
tabbies had mutations in their copies of the gene, whereas striped
tabbies had at least one copy with no mutation. Also, the mutated
gene is one that blotched tabbies share with wild cheetahs whose fur
went from spotted to striped. This mutation explains the pattern, but
makes no distinction as to the color of the fur in cheetahs. A gene
called the Edn3 decides the colors in the fur patterns.
Tabby patterns only show up when cats begin to grow
hair, which is within their first seven weeks of gestation, carried
out while the embryo develops, by changing levels of Edn3. During
gestation, levels of Taqpep increase. The Taqpep mutation happening
earlier on in a cat's life may determine why spots and stripes don't
change as the cat grows older. The main researcher in the study
speculated that the gene has other functions, and may do more for the
cats than simply change their patterns, such as helping boost
immunity against disease and infections.
